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Munc18-1 binding to the neuronal SNARE complex controls synaptic vesicle priming.

Authors: Deak, F  Xu, Y  Chang, WP  Dulubova, I  Khvotchev, M  Liu, X  Sudhof, TC  Rizo, J 
Citation: Deak F, etal., J Cell Biol. 2009 Mar 9;184(5):751-64. Epub 2009 Mar 2.
Pubmed: (View Article at PubMed) PMID:19255244
DOI: Full-text: DOI:10.1083/jcb.200812026

Munc18-1 and soluble NSF attachment protein receptors (SNAREs) are critical for synaptic vesicle fusion. Munc18-1 binds to the SNARE syntaxin-1 folded into a closed conformation and to SNARE complexes containing open syntaxin-1. Understanding which steps in fusion depend on the latter interaction and whether Munc18-1 competes with other factors such as complexins for SNARE complex binding is critical to elucidate the mechanisms involved. In this study, we show that lentiviral expression of Munc18-1 rescues abrogation of release in Munc18-1 knockout mice. We describe point mutations in Munc18-1 that preserve tight binding to closed syntaxin-1 but markedly disrupt Munc18-1 binding to SNARE complexes containing open syntaxin-1. Lentiviral rescue experiments reveal that such disruption selectively impairs synaptic vesicle priming but not Ca(2+)-triggered fusion of primed vesicles. We also find that Munc18-1 and complexin-1 bind simultaneously to SNARE complexes. These results suggest that Munc18-1 binding to SNARE complexes mediates synaptic vesicle priming and that the resulting primed state involves a Munc18-1-SNARE-complexin macromolecular assembly that is poised for Ca(2+) triggering of fusion.

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CRRD Object Information
CRRD ID: 2311128
Created: 2009-06-26
Species: All species
Last Modified: 2009-06-26
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.